While some organizations may have their own style guides outlining their unique preferences, the following 14 guidelines are how numbers should be used, absent a formal style guide in your organization.
1. Use Arabic numbers (1, 2, 3,) for:
• All numbers over nine in the text
There were 98,526 wafers in that batch. There were 10 operators involved. (But: Ten operators were involved.)
Note that when the first word of a sentence is a number greater than nine, you have two options: (a) spell it out, or (b) re-write the sentence so it does not start with the number. The exception is a numeral that identifies a calendar year.
• The day and year of the date:
April 10, 2014
5:25 A.M.; 4 P.M.
13535 N.W. Science Park Drive
8600 S.W. 10th Avenue
2700 N.E. Third Avenue
• Measurements, decimals, money, percentages:
5 in. (or 5 inches)
• In a series. Combine as appropriate (AP Style)
…15 cashews, three walnuts, 52 peanuts,…
• When modifying a noun
1/8-ft. lengths, 3-1/4-in. pipe
2. Spell out when:
• The number is the first word in a sentence
Ten operators were involved.
• The number is less than 10
three containers of filters
3. Other things to remember:
• Put a zero before the decimal point for a number less than one (0.543).
• Line up on the decimal point for lists of numbers (e.g., in a table).
• Combine Arabic numbers with words for large numbers (i.e., 200 million, $345 billion).
• For contracts, checks, and other documents where a typographical error could be really serious, spell out and use Arabic numbers [nine thousand twenty four dollars and twenty cents ($9,024.20)].
Hope these number guidelines will be helpful. They will also work for general business writing. Next week: Three easy ways to “translate” your words and terms to improve non-technical reader comprehension.
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Gail Tycer offers business writing workshops and presentations, executive coaching, consulting, and writing services. To discuss how we can help, call Gail at 503/292-9681, or email firstname.lastname@example.org